In good times, Lena (Natalie Portman), a cellular biology professor at Johns Hopkins, curls up on leisurely afternoons with her handsome-but-no-genius husband, Kane (Oscar Isaac).For pleasure, she reads “The Immortal Life of Henrietta Lacks,” the true story of an African-American woman whose infinitely reproducing cells gave rise to the most famous cell line in medical research — the ultimate split-cell “herstory.”Those are good times. “Annihilation,” based on Jeff VanderMeer&rsquo …